Physicists have created a miniature version of Harry Potter’s invisibility cloak (though it works only in microwave light, and not visible light, so far) in what they claim is a step closer to realizing the kind of invisibility cloak that could hide a person in broad daylight. It’s not exactly The Predator cloak, but hey, we’ll take it.
A new material created from strips of copper tape attached to a flexible polycarbonate film called metascreen has allowed this invention to work, and while up until recently most attempts to create invisibility have attempted to bend light rays around an object ( a technique that relies on so-called bulk metamaterials) so that they don’t scatter or reflect off of it, metascreen has incorporate copper strips at 66 micrometers (66 millionths of a meter) thick, with the polycarbonate film at 100 micrometers thick, to create a combined diagonal fishnet pattern.
This technique dubbed mantle cloaking, cancels out light waves that bounce off the shielded object so that none survive to reach an observer’s eye. Study co-author Andrea Alu, a physicist at the University of Texas at Austin, said in the following statement:
“When the scattered fields from the cloak and the object interfere, they cancel each other out and the overall effect is transparency and invisibility at all angles of observation,”
Alu and his colleagues successfully hid a 7-inch-long (18 centimeters) cylindrical rod from view in microwave light during lab experiments and they say the same technology should be able to cloak oddly shaped and asymmetrical objects, too. The advantages of the metascreen tests over the light bending is that the meatscreen materials are infinitely cheaper and easier to process. And in principle, the same kind of cloak could be used to hide objects in the visible range of light, but so far it’ll only work on small ones like the aforementioned rod.
“In fact, metascreens are easier to realize at visible frequencies than bulk metamaterials and this concept could put us closer to a practical realization,”
“However, the size of the objects that can be efficiently cloaked with this method scales with the wavelength of operation, so when applied to optical frequencies we may be able to efficiently stop the scattering of micrometer-sized objects.”
Just get back to me when it can cloak me from hardened military targets I’m hunting, while jumping tree to tree in the Colombian Jungle….